Synchronizer



I KO

M. L. SEVERY May 30, 1933.

SYNCHRONI ZER Filed June 15 1929 Nlom M mm mm o H I mm 1. M

duct wows Patented May 30, 1933 UNITED STATES PATENT OFFICE MELVIN L. SEVERY, DE LOS ANGELES, CALIFORNIA, ASSIGNOR TO THE VOCALSERVQ I 9 COMPANY, OF LOS ANGELES, CALIFORNIA, A CORPORATION OF DELAWARE SYN'CHRONIZER Application filed June 15,

This invention relates primarily to devices for synchronizing impulses to a definite, predetermined rhythm as, for example, the pitches of a musical scale, though it is also appplicable to the far less exacting duty of an ordinary speed regulator.

In Letters Patent N 0. 1,464,729 issued to me August 14th, 1923, I show means for producing tones of various p tches through the agency of revolving members and. where these tones are to be used for musical purposes, it is desirable to control their various pcriodicities with the utmost nicety or exactness, a result most effectively atta ned through the invention forming the subgectmatter of this application.

Briefly stated, the invention consists in a driving and a driven member with a slippage factor introduced between them, this slippage factor being controlled in extent by braking means, the braking effect being varied in amount in strict accordance with any variation in the rotation of the driven member, and thus varying the effective energy of the drivin member. I D

A very important feature of the invention is the means whereby, when the correct speed is reached, the relative movements of the gears in t drulm practically cease,

He thus securing a very quiet mechanism and one which is free from wear.

Another important feature of the invention is the balancing of the parts so that the whole structure shall be sensiblv free from vibration during operation, and so that any thrust tendencies shall mutually offset each other. I

Still another important feature of the invention is the designing of the relative gear sizes so that the braking factor may act with the advantage of a proportionally greater leverage, thus minimizing the power necessary to actuate the braking mechanism.

Other advantages, such. as compactness, sturdiness, long life, ease of maintenance of operation, etc, will appear as the description proceeds.

In the accompanying drawing:

Fig. 1 is a sectional view showing as a 1929. Serial No. 371,211.

part thereof the brake-controlling finger in the driven device, its relay, and associated mechanism;

Fig. 2 is a face or plan view of a portion grease-tight while mechanically free. 4 and l 5 designate bearings rising from castings 6 and 7 indicated by dotted lines, these cast ings being bolted to a base-plate 8 also shown in dotted lines. 9 indicates the central shaft, to one end of which is secured by a pin 10, a motor coupling 11, the drum 1 being correctly positioned on shaft 9 by means of a collar 9*, as seen in Fig. 3. 12 indicates sleeves of special bearing metal pressed into the bearings 4 and 5, and 13 the grease cups for lubricating said bearings. A pulley 1 1 adapted to take a belt, is secured to drum 1 by a set-screw 15, and 0perates as if integral with the drum, as it may in fact be made. In Fig. 3'I show the belt, as 16, extending about the drum 1, since such arrangement makes the construction easier of comprehension, and is the mechanical equivalent of placing the belt about the pulley 14 which is fast on the drum.

Within the drum 1 is a gear 17, preferably of bakelite or fiber, securely fastened to the central shaft 9 by a pin 17, said gear meshing with two bronze pinions 18, 19 which are firmly secured to bakelite gears 20, 21, as more clearly shown in Fig. 3. Secured to the bakelite gears 20, 21 by screws 22 are metallic sections 23, which form in each instance, a sleeve extending into the associated pinion 18 or 19, thus forcing said gears to turn therewith. Studs 24 securely bolted lGO to a revolvable disk 25, serve as bearings about which the bakelite gears 20 and 21 and their connected metallic pinions 18, 19 revolve upon antifriction sleeves 26. A similar sleeve 27 is used for a like purpose in connection with the disk 25, while a thicker ant-itriction sleeve 28 serves to support the end of shatt 9 centrally within a boss 29 on the drum 1. The bakelite gears 20, 21 mesh outwardly with a metallic annulus 30, and inwardly with a single bronze pinion 31 provided with a long sleeve to one end of which is secured by a set-screw, a disk 32 carrying a copper annulus. An antitriction bearing 31 lines this long sleeve, to ensure better action in operation. indicates the copper annulus secured to the edge of disk 32, the annulus 33 extending between the poles of electromagnets 3st and 35 which, when duly energized, operate to produce a retarding or braking action upon said annulus, incident to movement of the annulus 33 between the poles of the magnets. The disk 32 and attached copper annulus 33 constitute What may be termed a floating element intermediate the driving and driven elements.

I have shown two braking magnets but it is obvious that any desirable number may be used, or even one continuous electromagnet extending circuml'erentially entirely around the copper annulus l find, however, that two are usually suflicient. As here shown. magnet ill is normally energized continuously, while magnet 35 operates inter mittently under the action of a centrifugal linger 36 which serves to energize the relay magnet 37 controlling the intermittentlyacting braking magnet The two braking magnets are identical in type, as shown, but they are not necessarily of the same winding and power. since. it is generally preferable to have the intermittent magnet handle only enough current (that is to say, have only enough power), to make sure that it can handle all influences tending to slow down the mechanism with a thoroughly saite margin of excess. Among the influences so tending to slow down the mechanism arc drop in line voltage, variation in load, and slight frictional changes. Magnet 34, which normally is continuously energized. will, on the other hand, be given strength sutlicient to speed the device as near to the correct pitch as it is safe to come, due regard being had to fluctuants tending to raise voltage decrease load, or reduee triction. These magnets and their associated parts constitute inductive clutches.

The magnets Ill, 33 here illustrated each comprise a core 38 screwed or otherwise fastened to an armature or yoke :35) of magnetic material, said yoke forming the other pole of the magnet in each case. The yoke 39 is fastened to the casting 4O rising from the footing-plate ll shown in dotted lines,

said plate being secured to the main baseplate Casting -10 stiffened by ribs 4-2. 13 indicates binding posts for magnet leads, and ll, l5, designate wires leading from the binding posts to adjustable rheostats l6, l7. These rheostats are of conventional type and need no extended description. A movable finger lS, in each case, serves to vary the amount of resistance inserted in the line, and thus to regulate the strength of the associated magnet.

As seen in Figs. 1 and 2, 45) indicates a portion of the periphery of a pulley or wheel containing the centrifugal finger mechanism, 50 indicating the box housing the same. 5i indicates a non-ironducting block pivoted to the rear wall of housing 50, said block carrying upon its radially outermost side a substantial arm 52, the more flexible and longer contact-finger 36 being carried upon the opposite surface of block 51. A screw 53 bears upon arm 52, the outermost end ol said screw being fastened to a crank-arm Til provided with a pin at its outer end adapted to drop into holes serving as placement detcnts, as clearly shown in Fig. A cover 56 which may be removed when it is desired to reach the adjusting arm 5t, prevents entry oi dust and dirt. 57 indicates a wall of the linger-box 50, this wall also being removable. indicates an insulated abutment against which the contact linger iltj is pressed by the inward rocking of arm 52 when screw 53 turned in for purposes of regulation. so indicates a substantial plate of insulating material, secured to the lingcrdiox 3t) and having secured to it a metallic member 60 carrying a rcvolvablc silver contact-disk or which is resistively adjustable to provide for any tendency to 'pit" over long periods, under the action of the current. The contact-linger 36 also carries a silver contact 62, adapted to coact with do. til. when the speed passes the prcdetermineil limit to the slightest operable degree.

here a high type of synchronism is desired I find, for reasons which will be obvious, that it is not well to take the rela tively strong current which normally actuatcs the braking magnets l-l 3:"), through the box 0. This may be done in special cases, but ordinarily I prefer to use a relay so as to make the current traversing the cmitact-tinger 36 as slight as convenient. l n further conformity with this same general aim. I provide a condenser 63 to absorb the spark when finger 36 breaks contact with the coacting disk (3t. The relay inst referred. to is diagrammatically illustrated in the drawing as follows: 37 indicates the actuating magnet previously mentioned; (34, the swinging contact-armature; 65, the spring against which magnet 37 acts; 66, the coacting contact of the armature against which spring tends to press said armature; and 67 an adjustable stop to vary the distance of the armature from the magnet core at its inboard stroke, this stop acting with contact 66 to limit the beat of the armature in operation. 63 indicates a condenser across 64 and 66, to absorb the spark at the break of the contacts. In operation the linger 18 of the rheostat l6 in series with magnet which is normally continuously energized, is moved so as to cut out its resistance until the device speeds up to a point as near to the actual speed wanted as is safe, due allowance being made for fortuitous fluctuants tending to make the mechanism run faster. The finger 48 of rheostat 47 which controls the intermittentfinger-actuated magnet 35 is then pushed to cut in as much resistance as is possible and still secure a speed safely too fast when the magnet is held on steadily by manipulating the relay to that end. This secures an operation between safe limits, and as delicate in its characteristics as is permissible.

Explaining the operation of the device, an electric motor (not shown) is presumed to be connected to the coupling 11 to turn shaft 9 in a clockwise direction when facing said coupling, the copper annulus 33 being left free to turn. The result. will be as follows, it being understood that the drum 1 is held motionless: Annulus 33 will. revolve clockwise; gear 20 will revolve about its own axis anticlockwise, while rolling about the annular gear 30 in a clockwise direction, the pinion l8 integral with said gear 20' of course revolving with it in. the same direction; and the bakelite gear 17 which. is pinned to shaft 9 will. of course revolve in a clockwise direction forcing the pinion 18 integral with gear 20 to turn anticlockwise as aforesaid. Under these conditions, drum 1 and its belt 16 being stationary, no useful work is done, everything going into slippage at the free copper annulus. Suppose, now, that drum 1 is released and annulus 33 held stationary, while the motor turns in the same clockwise direction as before. The results will be as follows: All parts secured to the central shaft 9 will, of course, turn clockwise, that is, the central bakelite gear 17 will turn in this direction; drum 1 will also turn in the same direction and with it the annular metal gear 30; the bakelite gear 20 meshing into annulus 30 will turn with. it, and at the same time will revolve about its own center in a clockwise direction, the disk 25 also revolving clockwise. Under this latter condition of affairs the speed of the dri ing belt 16 will be at its maximum, while under the former condition it will be at its minimum. If, now, the copper annulus 33 be not held tightly, but be allowed to slip more or less, it will be seen that just in the ratio that it is allowed to slip will the driving belt slow down in speed, while just in the ratio that said annulus is held against slippage will the driving belt tend to speed up. The mechanism is, therefore, so planned that if annulus 33 be held rigidly, the speed will be greater than wanted, while if it be allowed full freedom it will be less than wanted, it is manifest that the desired speed will be attainable between these limits by applying the correct amount of retarding influ ence to the annulus 33. It is to be noted that when annulus 33 is held rigidly, the gear movements in the drum (as related to each other) are very slight, but when the drum is held rigidly, the annulus 33 being allowed. to take up the motion, the gear movements (relative to each other) are very considerable. In the interest of quietness I accordingly aim to proportion the parts so that, at the desired speed, the copper annulus 33 and the drum shall be revolving together at a constant rotative speed, or as nearly thereto as is feasible. The rheostat associated with the constant braking influence is regulated to cause the device to come as near the correct speed as is safe, as aforesaid, and then the intermittent inductive clutch is so regulated that if it operated practically continuously, it will drive the device a safe margin too fast.

It will be noted that l regulate both my inductive clutcl'ies by the use of resistances, but it is to be understood that I do not confine myself to this n'Jea-ns, since it is perfectly obvious that the same thing could be accomplished in several other ways. For ex.- ample, the cores of the clutch magnets might be brought adjacent the copper anuulus at different radial lengths from its center of motion, in which case the same force would act at different leverages; or again, different portions of the core areas of the clutch magnets might be removed radially beyond the copper annulus; or both these cxpedients might be employed. Indeed, I do not even confine myself to an inductive brake of any sort as it is obvious that I might use mechanical, pneumatic, or other braking means for one or both of my inductive clutches. A fan with adjustable blades might serve very well, for at least the continuous brakii'ig action, especially under conditions where a motor needed air-cooling, but ordinarily, and particularly in the case of'the intermittent clutch, I prefer the inductive form shown since it lends itself to the best attainable results.

The be); 50 containing the finger 36 and its associated mechanism may be placed within the drum 1 in the position indicated by the numeral 69 in Fig. l, or at any other suitable place in the system. However, as the mechanism contained in said box, when placed at the point 69, has no power over perturbations taking place between the drum and the mechanism to be synchronized. I prefer to place said mechanism at the point to be synchronized. a is shown in the drawing. The operation of the mechanism within said box. when starting from rest. is as follows:

The contact-finger 36 is out of touch with its co-acting silver disk 61 so that the relay magnet 37 is decnergized. permitting the spring (35 to pull the swinging contact-armature ()4 into touch with its co-acting contact- (itl, thus energizing the intermittent clutch magnet 35 which tends to resist the motion of the annulus and so to cause the ce to speed up. The continuously operating magnet 34 is energized with the starting of the device so that. all factors make for speeding up and the speed rise: accordingly until the critical speed is r .+ached at which the centrifugal contactfinger 36 rises into touch with the coacting silver disk 61. Vhen this occurs. current flmvs from the source and wire 71 via the disk (31 to the linger 36; thence by wire 72 to relay magnet 37; and from the other pole of said magnet by wire 73 back to the source 70. n'is instantly energizes the relay magnet 37 and causes it to break the contact between armature (lat and the co-acting contact ('36. thus deenergizing the intermittent clutch magnet and permitting more slippage of the cop per annulus 3 with a consequent decreased speed of the driving belt- 16, or other power transmitter. as soon as the centrifugal finger 36 break; contact with the silver disk 61.. the intermittent clutch magnet- 35 will again become active. and speed up the device until the parts again operate and the contact is renewed. In this way the mechanism is constantly crossing a predetermined speed by increments and decrements so infinitesh mill. due to the extraordinary delicacy of action of the centrifugal finger and the rapidity of electrical action. that to all in te ts and purposes it holds the one speed sensibly constant. even a highly trained car being unable to detect the minute variations which are present according to theory.

I have shown the linger 36 as making contact with disk 61 on rii-ic of speed. but I do not limit 111:"?if to this form of action since it is pcrfectl obvious that. by adjusting certain of the other factors. contact could ju t as well be effected by decrement. of spec l. The form I have shown. however. seems to be the most natural. and for this reason I prefer it.

As indicated in the opening part of this description. the present invention is designed more par icularly for synchronim ing the speed of the prime mover with the definite. predetermined and invariable pcriodicities necessary to provide the pitches of a musical scale produced by an inst-rument of the type disclosed in Letters Patent No. 1.464.729, before mentioned. Fig. 4

sho sufiicient of such an instrument to i1- lustratc the use therewith of the synchronizer herein described. In said figure, 74, T5, 76 indicate resonators each having at its lower end a diaphragm 77 carrying a movable core 78 of an electromagnet. the coils of which are fixed and encompass said core. On rotation of the shaft- 79 carrying the peripherally toothed or crested disks or armatures 80. the diaphragms 77 are caused to reciprocate or vibrate, and thereby to produce sound-waves of the exact periodicities to iause the stveral resonators each to give forth its predetermined note of the musical scale. The shaft 79, which of course is carried in suitable bearings. carries the drum 1 of the synchronizer, other parts of the mechanism being omitted from this greatly reduced figure. It is of course to be under; stood that this specific arrangement of the motor, synchronizer, and musical instrument, is illustrative only, and may be varied as desired.

I claim:

The herein described synchronizing comprising a driving member capable of developing a safe excess of speed; a driven member to be brought to and kept sensibly at. a n'edetcrmined cimstant speed despite line. load. and frictional tluctuants; inductive braking means; an interposed geared member controllable by said braking means and adapted when left free, to prevent a sufiiciency of the driving speed from being cmnmunicatcd to the driven member; gears connected with said interposed member and so proportioned as related to each other and to the other parts of the mechanism as to have little or no interaction when the device is running at the predetermined speed; and centrifugal means controlled by the speed o t the driven member and serving to bring about variation in the retarding influence exerted upon said interposed member and thus to bring the driven member to and maintain it at, the predetermined sensibly constant speed.

In testimony whereof I have signed my name to this specification.

MELVIN L. SEVERY. 

